1.Field of the Invention
The present invention relates to a magnetostrictive material, and particularly, to a magnetostrictive material including a rare earth element and a transition metal element, and a process for producing the same.
2.Description of the Related Art
This type of magnetostrictive material is conventionally known as disclosed in, for example, Japanese Patent Application Laid-open No.1-246342.
However, the known magnetostrictive material suffers from a problem that when a magnetic field is applied thereto, this material is deformed, with its volume remaining substantially constant, in a direction of the magnetic field due to the fact that the density is set at approximately 100% with respect to a theoretical density in order to make its mechanical strength high, and hence, the magnetostriction amount is relatively small.
The magnetostrictive material is used for forming a fuel injection valve in an engine for an automobile, as disclosed in, for example, Japanese Utility Model Application Laid-open No.3-35260 and Japanese Patent Application Laid-open No.6-58445. The mechanical strength required for the fuel injection valve or he like may be relatively low and hence, it is required that the magnetostrictive material used for the fuel injection valve or the like have only a practical mechanical strength and moreover, have a larger magnetostriction amount.
Accordingly, it is an object of the present invention to provide a magnetostrictive material which has a practical mechanical strength and also has a substantially increased magnetostriction amount.